As shown in FIG. 1, a conventional lamp apparatus includes two substantially inverted truncated V-shaped frames 11 (only one is shown) connected horizontally to each other and cooperatively defining a mounting space 110, a lamp holder 12 mounted in the mounting space 110, a clamping member 13 clamped outside one of the frames 11, and a screw 14 penetrating the clamping member 13 and having an end abutting against one of the frames 11. Each of the frames 11 includes a base wall 111, and two clamping grooves 112 that are respectively formed in opposite sides of the base wall 111 and that open outward. The clamping member 13 includes a flat portion 131 extending horizontally, a screw hole 132 formed in the flat portion 131, and two clamping portions 133 extending respectively and obliquely from opposite ends of the flat portion 131 and respectively have ends 134 that are bent inward to form hooks. The ends 134 of the clamping portions 133 respectively engage the clamping grooves 112 in the frames 11.
Since the clamping member 13 clamps to the clamping grooves 112 of the frames 11 through the ends 134 of the clamping portion 133 merely, the ends 134 of the clamping portions 133 tend to come loose from constant deformation due to long-term or repeated use which may lead to falling of the frames 11 from the ceiling and cause accidents. In addition, because the clamping member 13 is disposed between the lamp holder 12 and the ceiling, adjustment and handling of the clamping member 13 by a user who is below the lamp holder 12 are complicated.